"We jumped outta the back spitting sweat and blood. Plasma fucking everywhere! We thought we were screwed when the Prowler turned up but the gunner just stuck two rounds in it and popped it then went berserk on the building. Brutes and concrete ain't much against a thirty mike-mike."

―Corporal Jenna Griffon

The M3 Crocodile is a amphibious infantry fighting vehicle used by the UNSC for frontline infantry transport, with sufficient armour and weapon systems to provide a suitable firebase for the embarked infantry units.

The M3 Crocodile was designed to fulfil requirements for both the UNSC Army and Marine Corps, being a heavily armed, well armoured amphibious AFV, capable of keeping up speed with the common M808G Scorpion Main Battle Tank and follow it off road, through rough terrain. The Crocodile has a familiar layout, with a low, sleek profile, heavily sloped frontal armour and a mid placed gun. The driver is placed at the front left of the tank, with access to regular system controls for controlling a tank, along with a 360 degree holographic readout and heads up display. The drive can raise his seat to manually observe the battlefield, using the view port above his head. Next to him is the commander, with access to the battle systems and the remote weapon, and a similar hatch for viewing. Behind the commander is the turret operator, viewing the camera nexus attached to the turret, allowing him to fire on the targets to his front. Behind them is the nine seats for infantrymen embarked on the vehicle. These infantrymen have access to the vehicle's air conditioning, on-board coffee machine, on-board chargers for their body armour and access to the data systems.

The on-board weapon systems consist of a automated weapon turret, carrying and inboard 30mm autocannon, capable of firing up to 250 rounds a minute. The gun is fed from two belts of three hundred rounds each, allowing the gunner to swap feeds based on changing requirements. The gun has a co-axial M247H2 Heavy Machine Gun, firing .50 calibre rounds, allowing the gunner to engage infantry in cover with ease. The gun could be raised or depressed to extremely high levels, reducing close in 'dead zones' and allowing it to engage low flying aircraft.On each side of the turret is a recess carrying a single MGM-34 Fang Anti Tank Guided Weapon. The Fang ATGW is incredibly deadly against armour, being capable of flattening most armoured vehicles. These fold out and use the vehicle's own RADAR targeting package to lock on to a target and launch. These weapon bays can be reloaded internally by the crew, rather than having to risk exiting the vehicle to replace them. The turret is fully stabilized so it can be fired on the move as well as from a stationary position, and features a 360 degree sensor network, consisting of clusters of optical and infra-red cameras, forward facing digital optical and hyridized night vision/thermographic, with full zoom features, LIDAR, which functions to both identify targets and terrain and preform range finding duties and a fire control RADAR for identifying targets and preforming short range anti-air threat detection. Mounted on top of the turret structure is a PALADIN Weapon Station, controlled by the commander. This can fit heavy machine guns, miniguns, grenade launchers, autocannons or more exotic weapons, like LASERs, or microwave weapons. This allows the vehicle to be augmented to face predicted threats on the battlefield, most of the time providing close in protection against infantry.

Later in the war, the Crocodile was upgraded with a 30mm rail gun capable of high rates of fire. This, mixed with explosive and armour piercing rounds availible for it increased its lethality against both soft and hard targets, such as infantry, armour and structures.

The vehicle has a wide range of defensive measures. Aside from its armour plating, constructed from sandwhiched layers of titanium alloy and AEGIS tiling, with specialised layers to absorb heat, catch spalling and dissipate shock, the vehicle can also be fitted with non-explosive reactive tiles and wrap around cage armour to protect against explosive warheads. From primary threat detection against missiles, artillery, mortars and rockets, it has a AURORA LASER, which is a hard-kill point defence LASER, capable of igniting warheads in less than a half a second. To protect against medium yield anti-armour plasma weapons, such as fuel rod guns, plasma launchers and concussion rifles, and against hard kill munitions such as anti-tank shells and plasma mortars, it possess the CARAPACE DAPS. For light plasma munitions it deploys a magnetic field that deflects them away. For heavier munitions, it deploys a short use bubble shield to stop this munitions entirely, though cannot return fire in this event. The REBOUND Passive Defence System activates in the event of a LASER lock on the vehicle, deploying LASER emitters, usually placed strategically to defend the vehicle. It will then modulate and adapt the beams to the wavelength of the tracker, which takes between 0.4 and 0.6 seconds and then initiate decoy beams, giving the missile alternating and confusing signals, in the hope these will send it off course or rebound it back to it's launch platform. The NOCTURNAL Passive Defence System uses an infra-red blinding system to dazzle oncoming missiles and send them off course, allowing it to stay safe against infra-red guided missiles. The BLINDER Passive Defence System is a Area Defence and Interception System linked system that is kicked into motion when both a RADAR tracker and missile threat are detected. It works by using a extremely high power but extremely small transmitter made of advance plastic formed metamaterials. These antennae are capable of modulating and attuning to the guidance of the incoming ordnance and spoofing the RADAR, whether it is RADAR guided, GPS assisted or Radio guided and disrupt its lock and sends it off course. Lastly, the NEMESIS Decoy Launcher is a all round defensive system utilising a number of strategically positioned decoy launchers, using three rotary barrels that can be independently loaded from a magazine of fifty caseless munitions. The munition choices include High power Infra-red flares, designed to blind infra-red, ultra-violet and night vision systems with high intensity lights, with variable 'dial' settings controlled by ADIS and FAI parameters to adjust it's brightness and intesity in various spectrums, to allow to to match vehicle signatures or to simply blind targets, Ion flares, producing strong electromagnetic fields, capable of generating false signals on magnetic detection systems, confusing magnetic guidance system such as MAD guided missiles or magnetic tunnel guided munitions such as plasma launcher munitions. The variable settings on Ion Flares allow them to either produce a wide band jamming signal or producing false signals, Smoke generators, producing a non-toxic smoke. The smoke mixture has a number of high energy particles mixed in, which when ignited generate a high thermal signature across the entire smoke cloud, which can cover up to forty metres, creating a thermal 'blotch', wherein vehicles can safely hide, RB-3 aerosol composites that disperse in a prearranged cloud detonation to diffract DEWs with a 79% effectiveness, Chaff dispensers, which confuse RADAR guidance and detection systems within a wide area around the vehicle. These utilise a wide variety of alluminium composite strips, designed to cause massive intereference over a wideband, with more narrowband optional flares to create a protective blanket that does not blind their own RADARS, AN/ULQ-399 Variable Mission Programmable Radio Decoy (VAMPR, more commonly referred to as 'VAMPIRE') is a multi-purpose radio decoy, with a number of capabilities that can be programmed by the ADIS or FAI before launch. The VAMPR is capable of emitting spoofing signals, beam false co-ordinates to the RADAR seeker of the missile or opposing fighter, producing a wide range of false signals matching the launch platform to confuse missiles with false RADAR targets, wide ban jamming or narrow ban jamming or simply blinding RADAR guided ordnance, RM-11 composite dispersal is a specialised dispersal pod that covers an area in a dense field of titanium dust. This dust has a high effect against plasma munitions, causing premature detonation and reduction of munition density, causing plasma munitions to lose their power against the target.

The vehicle moves through water using water jets and can move at 45 KPH. It also features a hydraulic trim vane that lowers over the front plate to improve hydrodynamic performance. The vehicle is water tight and can ford depths up to 2 metres. It also has full CBRN protection and in the unlikely event, internally it has a homogenizing field that decontaminates any material leaving or entering the vehicle. The rear door is powered by an electric ram, which can be powered by a hand crank inside the vehicle.

The vehicle is used by both the UNSC Army and UNSC Marine Corp for transporting infantry in mechanised and armoured formations, where it can safely transport them to the front against a multitude of threats and drop them off, providing a mobile firebase once it has dropped them off.

UNSC Remarks

"A fine vehicle. I owe my life to having one of these instead of Camel on alotta times."

"Alotta boys complain that there aren't fire ports in this thing, better that way. Means theres more room and less holes to get shot through."

"During some of the Rat Pack Patrols off Highway 19, our Croc got hit in the track by a Fuel rod. One in a million chance but we lost the tack and had no gear to repair it. For the next ten hours us and the 'roo held off waves and waves of Remants. By the time morning hit we got picked up by a Pelican. We only lost two guys, with a few more wounded cos we just moved into the Croc when shit got heavy."